Intra-uterine systems that can be implanted and recovered non-invasively have been known for a number of years.
Generally speaking, these systems can be classified into three major families according to their indication or their mode of action. Of these, devices having an anti-conception indication, such as contraceptive IUDs, represent the great majority of cases and constitute the first category.
The second category consists of capsules loaded with a therapeutic substance and placed in the uterine cavity for diffusion and action in the organism.
Finally, the third category consists of intra-uterine devices indicated for in vivo assistance in medically assisted procreation processes. Thus there is known an intra-uterine device as notably described in the document WO 03/011200, intended to be placed in the uterine cavity for a period between a few hours and a few days, and enabling pre-implantation development of an embryo in vivo.
For each of these categories of devices, it is of primordial importance that the object placed in the uterine cavity non-invasively can remain positioned at the determined location for the indicated period and then recovered non-invasively.
To meet these specifications, the devices concerned must address two constraints, a priori contradictory. On the one hand, these devices must be both thin and compact to be placed in the uterine cavity and then removed, non-invasively, which imposes the passing through the cervical channel of the cervix. Moreover, they must be sufficiently bulky to be stabilized in the uterine cavity and not to be expelled by the natural contractions of the uterus.
In the prior art numerous variants and shapes have been proposed to address this two-fold constraint, but oriented exclusively to applications belonging to the first and second categories of devices described above.
Now, for the third category of devices used in the process of medically assisted procreation in vivo, an additional constraint becomes apparent when it is of primordial importance to preserve the integrity of the endometrium. This is because implantation of the embryo must take place in the same menstrual cycle of the patient and the endometrium must not be damaged in any way prior to implanting the embryo.
In particular, existing stabilization systems in the field of contraception, and in particular for retaining a contraceptive IUD in position in the uterus, are not satisfactory. This is because they can damage the endometrium, not only when retaining the device in position in the uterine cavity, by exerting a constant pressure against the endometrium (causing phenomena of contractions, possibly with hormonal activation), but also during removal of the device, the retaining elements rubbing on the endometrium over a great distance, thereby causing microlesions or inflammatory inductions, or bleeding.
Also, the document WO 03/011200 describes an intra-uterine device carrying stabilizing fins at a distal end of the housing. These stabilizing fins are liable to damage the endometrium, notably during removal of the device, and thereby to reduce the chances of successful subsequent implantation of the embryo.